You can achieve a similar effect in IC2 by switching a storage block...
True but this method only works with the storage block until it is full and then it will start outputting again. In which case you are still going to be bleeding energy.
Though I didn't realize until now that you are right and applying red stone to a transformer would have a similar effect as the switch did. Though that does complicate matter quite a bit. It would require more resources for the transformers and would make the electrical wiring and red stone wiring a mess. I would still hope for a way to be able to directly shut off a power hungry machine such as the Mass Fabricator.